Complete Explanation:On May 27, 1861, Benjamin Butler, commander of the Union army in Virginia and North Carolina, decreed that slaves who fled to Union lines were legitimate "contraband of war," and were not subject to return to their Confederate owners. The declaration precipitated scores of escapes to Union lines around Fortress Monroe, Butler's headquarters in Virginia.

In this crudely drawn caricature, a slave stands before the Union fort taunting his plantation master. The planter (right) waves his whip and cries, "Come back you black rascal." The slave replies, "Can't come back nohow massa Dis chile's contraban." Hordes of other slaves are seen leaving the fields and heading toward the fort.